A primary surface 23a of a supporting base 23 of a light-emitting diode 21a tilts by an off-angle of 10 degrees or more and less than 80 degrees from the c-plane. A semiconductor stack 25a includes an active layer having an emission peak in a wavelength range from 400 nm to 550 nm. The tilt angle “A” between the (0001) plane (the reference plane SR3 shown in FIG. 5) of the GaN supporting base and the (0001) plane of a buffer layer 33a is 0.05 degree or more and 2 degrees or less. The tilt angle “B” between the (0001) plane of the GaN supporting base (the reference plane SR4 shown in FIG. 5) and the (0001) plane of a well layer 37a is 0.05 degree or more and 2 degrees or less. The tilt angles “A” and “B” are formed in respective directions opposite to each other with reference to the c-plane of the GaN supporting base.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A group III nitride semiconductor device, comprising: a supporting base having a primary surface, the primary surface comprising a hexagonal compound, the primary surface tilting by an off-angle of 10 degrees or more and less than 80 degrees with reference to a c-plane of the hexagonal compound; and a semiconductor region provided on the primary surface of the supporting base, the semiconductor region comprising a semiconductor layer, the semiconductor layer comprising a hexagonal gallium nitride-based semiconductor different from the hexagonal compound, a tilt angle between a (0001) plane of the hexagonal compound of the supporting base and a (0001) plane of the hexagonal gallium nitride-based semiconductor of the semiconductor layer being in a range of +0.05 degree to +2 degrees and −0.05 degree to −2 degrees, and the hexagonal gallium nitride-based semiconductor of the semiconductor layer comprising one of AlGaN and InGaN.
2. The group III nitride semiconductor device according to claim 1 , wherein the semiconductor region comprises an active layer comprising a hexagonal gallium nitride-based semiconductor, the active layer is provided so as to emit light having an emission peak in a wavelength range from 400 nm to 550 nm, the active layer comprises an InGaN well layer, and the group III nitride semiconductor device includes one of a light-emitting diode and a semiconductor laser.
3. The group III nitride semiconductor device according to claim 1 , wherein the supporting base comprises one of sapphire, SiC and GaN.
4. The group III nitride semiconductor device according to claim 1 , wherein the supporting base comprises a gallium nitride-based semiconductor, and the primary surface has a semipolar surface.
5. The group III nitride semiconductor device according to claim 1 , wherein the supporting base has a gallium nitride-based semiconductor region having a threading dislocation density of 1×10 7 cm −2 or less.
6. The group III nitride semiconductor device according to claim 1 , wherein the hexagonal compound of the supporting base is GaN, and the tilt angle is defined by an angle between a (0001) plane of GaN of the supporting base and the (0001) plane of the hexagonal gallium nitride-based semiconductor.
7. The group III nitride semiconductor device according to claim 6 , wherein the hexagonal gallium nitride-based semiconductor of the semiconductor layer comprises InGaN, and the tilt angle is defined by an angle between the (0001) plane of GaN of the supporting base and a (0001) plane of InGaN of the semiconductor layer.
8. The group III nitride semiconductor device according to claim 6 , wherein the hexagonal gallium nitride-based semiconductor of the semiconductor layer comprises AlGaN, and the tilt angle is formed by an angle between the (0001) plane of GaN of the supporting base and a (0001) plane of AlGaN of the semiconductor layer.
9. The group III nitride semiconductor device according to claim 6 , wherein a <0001> direction of GaN of the supporting base is different from a <0001> direction of the hexagonal gallium nitride-based semiconductor in a transmission electron microscopic image.
10. The group III nitride semiconductor device according to claim 1 , wherein the hexagonal gallium nitride-based semiconductor is elastically distorted in a reference plane parallel to the primary surface of the supporting base.
11. The group III nitride semiconductor device according to claim 1 , wherein the supporting base comprises an A-plane sapphire substrate and a GaN layer provided on the sapphire substrate.
12. An epitaxial wafer, comprising: a wafer having a primary surface, the primary surface comprising a hexagonal compound, the primary surface tilting by an off-angle of 10 degrees or more and less than 80 degrees with reference to a c-plane of the hexagonal compound; and a semiconductor region provided on the primary surface of the wafer, the semiconductor region comprising a semiconductor layer, the semiconductor layer comprising a hexagonal gallium nitride-based semiconductor different from the hexagonal compound, a tilt angle between a (0001) plane of the hexagonal compound of the wafer and a (0001) plane of the hexagonal gallium nitride-based semiconductor of the semiconductor layer being in a range of +0.05 degree to +2 degrees and −0.05 degree to −2 degrees, and the hexagonal gallium nitride-based semiconductor of the semiconductor layer comprising one of AlGaN and InGaN.
13. The epitaxial wafer according to claim 12 , wherein the semiconductor region comprises an active layer comprising a hexagonal gallium nitride-based semiconductor, and the active layer has a peak wavelength between 400 nm and 550 nm in a photoluminescence spectrum of the active layer.
14. The epitaxial wafer according to claim 12 , wherein the wafer comprises one of sapphire, SiC and GaN.
15. The epitaxial wafer according to claim 12 , wherein the wafer comprises the gallium nitride-based semiconductor, and the primary surface has semi-polarity.
16. The epitaxial wafer according to claim 12 , wherein the wafer has a gallium nitride-based semiconductor region having a threading dislocation density of 1×10 7 cm −2 or less.
17. The epitaxial wafer according to claim 12 , wherein a maximum of a distance between two points on edges of the wafer is 45 mm or more, the hexagonal compound of the wafer is GaN, and the tilt angle is formed by a (0001) plane of GaN of the wafer and the (0001) plane of the hexagonal gallium nitride-based semiconductor of the semiconductor layer.
18. The epitaxial wafer according to claim 17 , wherein the hexagonal gallium nitride-based semiconductor of the semiconductor layer comprises InGaN, and the tilt angle is formed by the (0001) plane of GaN of the wafer and a (0001) plane of InGaN of the semiconductor layer.
19. The epitaxial wafer according to claim 17 , wherein the hexagonal gallium nitride-based semiconductor of the semiconductor layer comprises AlGaN, and the tilt angle is formed by the (0001) plane of GaN of the wafer and a (0001) plane of AlGaN of the semiconductor layer.
20. The epitaxial wafer according to claim 17 , wherein the <0001> direction of GaN of the wafer is different from the <0001> direction of the hexagonal gallium nitride-based semiconductor in a transmission electron microscopic image.
21. The epitaxial wafer according to claim 12 , wherein the hexagonal gallium nitride-based semiconductor is elastically deformed in a reference plane parallel to the primary surface of the wafer.
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May 13, 2010
January 18, 2011
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